Apparatuses and methods for displaying and receiving tactical and strategic flight guidance information

ABSTRACT

Methods and apparatuses for displaying and receiving tactical and strategic flight guidance information are disclosed. A method in accordance with one aspect of the invention includes displaying at least one first indicator to an operator of the aircraft, with a first indicator corresponding to a first instruction input by the operator for directing a first aircraft behavior and implemented upon receiving an activation instruction from the operator. At least one second indicator corresponding to a second instruction for directing a second aircraft behavior at least proximately the same as the first aircraft behavior is displayed, with the at least one second instruction to be automatically implemented at a future time. The at least one second indicator is at least approximately the same as the at least one first indicator. Indicators can be hierarchically organized to simplify presentation and reduce pilot training time.

This application is a continuation of U.S. patent application Ser. No.12/825,135 filed Jun. 28, 2010, entitled APPARATUSES AND METHODS FORDISPLAYING AND RECEIVING TACTICAL AND STRATEGIC FLIGHT GUIDANCEINFORMATION, which is a divisional U.S. patent application Ser. No.11/639,791 filed Dec. 14, 2006, now U.S. Pat. No. 7,751,948 issued Jul.6, 2010, entitled APPARATUSES AND METHODS FOR DISPLAYING AND RECEIVINGTACTICAL AND STRATEGIC FLIGHT GUIDANCE INFORMATION, which is adivisional of U.S. patent application Ser. No. 10/746,912 filed on Dec.24, 2003, now U.S. Pat. No. 7,188,007 issued Mar. 6, 2007, which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

The following disclosure relates generally to aircraft flight guidancesystems and to apparatuses and methods for displaying and receivingtactical and strategic flight guidance information.

BACKGROUND

Aircraft autoflight systems have evolved over the years from thetraditional autopilots for basic flight path control to complex flightmanagement systems capable of automatically flying aircraft overcomplicated routes without pilot intervention. Such flight managementsystems typically include an autopilot, an autothrottle, and a flightmanagement computer (FMC) interfaced with the autopilot andautothrottle. Flight decks on aircraft utilizing such systems generallyinclude a number of controls and displays that allow pilots to monitorthe flight management system and change autoflight parameters ifdesired. As flight management systems have evolved, these controls anddisplays have been positioned in different locations around the flightdeck. Over time, these locations have become somewhat standardizedwithin the transport aircraft industry.

FIG. 1A illustrates an aircraft flight deck 20 having a flightmanagement system in accordance with the prior art. The flight deck 20includes a first pilot seat 24 a and a second pilot seat 24 b, separatedby a control pedestal 26. Forward windows 21 are positioned forward ofthe seats 24 a, 24 b and provide a forward field of view for the pilots(not shown) seated in the pilot seats 24 a, 24 b. A plurality of flightinstruments 27 are positioned on a forward instrument panel 23 and thecontrol pedestal 26 for access by the pilots. A glare shield 22 ispositioned below the forward windows 21 to reduce glare on the flightinstruments 27.

The flight instruments 27 can include a number of autoflight controlsand displays, including a first control display unit (CDU) 28 apositioned on the control pedestal 26 adjacent to the first pilot seat24 a, and a second CDU 28 b positioned on the control pedestal 26adjacent to the second pilot seat 24 b. The first and second CDUs 28 a,28 b allow the pilots to make data entries into a flight managementcomputer (FMC) for controlling the flight management system. Theseentries can include flight plan information, e.g., strategic navigationand flight profile parameters. The flight instruments 27 can alsoinclude a first primary flight display (PFD) 25 a positioned on theforward instrument panel 23 in front of the first pilot seat 24 a, and asecond PFD 25 b positioned on the forward instrument panel 23 in frontof the second pilot seat 24 b. The first and second PFDs 24 a, 25 bdisplay actual flight parameters of the aircraft, such as airspeed,altitude, attitude and heading. In addition, the first and second PFDs25 a, 25 b can also display conventional flight mode annunciators(FMAs). FMAs are textual shorthand codes indicating the current modes ofthe autothrottle and autopilot. The flight deck 20 can further include amode control panel (MCP) 30 incorporated into the glare shield 22. TheMCP 30 provides control input devices for the FMC, autothrottle,autopilot, flight director, and altitude alert systems.

FIG. 1B illustrates a list 90 of existing FMAs corresponding toinstructions for automatically controlling the lateral motion andvertical motion of an aircraft, in accordance with the prior art. Asshown in FIG. 1B, existing arrangements can include at least ninedifferent lateral modes and at least ten different vertical modes forcontrolling the motion of the aircraft. Furthermore, the same aircraftflight path control may be annunciated by different FMAs depending onwhether the annunciation originates from the MCP 30 or the FMC. Stillfurther, a given FMA may represent very different flight path controls,depending on flight conditions and/or the state of the aircraft'sautoflight system.

One characteristic of the foregoing arrangement is that it is relativelycomplex. A potential drawback with this characteristic is that it can betime consuming and therefore expensive to train flight crews in the useof this system. As a result, the overall cost of operating the aircraftincreases, which in turn increases the cost of transporting passengersand goods by air.

SUMMARY

The present invention is directed generally toward methods andapparatuses for controlling aircraft. A computer-implemented method inaccordance with one aspect of the invention includes displaying at leastone indicator to an operator of an aircraft, with the at least oneindicator corresponding to at least one first instruction input by theoperator for directing a first aircraft behavior and implemented uponreceiving an activation instruction from the operator. The method canfurther include displaying at least one second indicator to theoperator, the at least one second indicator corresponding to at leastone second instruction for directing a second aircraft behavior at leastapproximately the same as the first aircraft behavior. The at least onesecond instruction is to be automatically implemented at a future timeand is at least approximately the same as the at least one firstindicator.

The indicators can correspond to maneuvers conducted by the aircraft,with at least generally similar maneuvers having at least approximatelythe same indicators, whether they are to be implemented imminently or ata future time. The indicators can correspond to lateral motion, verticalmotion, or air speed of the aircraft and can be automaticallyimplemented or manually implemented by the operator.

A method in accordance with another aspect of the invention includespresenting a plurality of first level options for controlling an aspectof the aircraft's motion, with at least one of the first level optionshaving associated with it a plurality of second level options. A firstinput corresponding to a selection of the at least one first leveloption is received, and the method further includes presenting aplurality of second level options corresponding to the at least onefirst level option. The method still further includes receiving a secondinput corresponding to a selection of one of the second level options.The first options can be presented as switch positions of a manualswitch having at least two positions, and the second level options canbe presented as text messages on a display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a flight deck of an aircraft having a flightmanagement system in accordance with the prior art.

FIG. 1B illustrates existing flight mode annunciators in accordance withthe prior art.

FIG. 2A is a schematic illustration of an aircraft having a flightguidance system in accordance with an embodiment of the invention.

FIG. 2B is a partially schematic illustration of a flight deck having aflight guidance system with displays and controls configured inaccordance with an embodiment of the invention.

FIG. 3 is a block diagram illustrating in a general manner the operationof a flight guidance system in accordance with an embodiment of theinvention.

FIG. 4 is a block diagram illustrating a method for displayingindicators for automatically controlling the motion of an aircraft inaccordance with an embodiment of the invention.

FIG. 5 is an illustration of lateral motion modes in accordance with anembodiment of the invention, along with existing lateral motion modes.

FIG. 6 is an illustration of vertical motion modes in accordance with anembodiment of the invention, along with existing vertical motion modes.

FIG. 7 is a flow diagram illustrating a method for presenting controlinformation and receiving control inputs at two different hierarchicallevels in accordance with an embodiment of the invention.

FIG. 8 is a front elevation view of a mode control panel having displaysand controls arranged in accordance with an embodiment of the invention.

FIGS. 9A-9B illustrate a portion of the mode control panel shown in FIG.8 for controlling lateral motion of an aircraft in accordance with anembodiment of the invention.

FIGS. 10A-10B illustrate a portion of the mode control panel shown inFIG. 8 for controlling vertical motion of an aircraft in accordance withan embodiment of the invention.

FIGS. 11A-11B illustrate a portion of the mode control panel shown inFIG. 8 for controlling the airspeed of an aircraft in accordance with anembodiment of the invention.

FIG. 12 is a flow diagram illustrating a method for arranging anddisplaying flight control information in accordance with anotherembodiment of the invention.

FIG. 13 is a flow diagram illustrating a method for displaying currentand proposed subsequent flight control information in accordance withstill another embodiment of the invention.

FIGS. 14A-14B are partially schematic illustrations of a mode controlpanel and flight plan list display, both of which have flight controlinformation displayed in similar manners, in accordance with anembodiment of the invention.

DETAILED DESCRIPTION

The following disclosure describes apparatuses and methods forreceiving, displaying and implementing flight guidance informationassociated with the control of aircraft. Certain specific details areset forth in the following description and in FIGS. 2A-14B to provide athorough understanding of various embodiments of the invention.Well-known structures, systems and methods often associated withaircraft flight guidance systems have not been shown or described indetail below to avoid unnecessarily obscuring the description of thevarious embodiments of the invention. In addition, those of ordinaryskill in the relevant art will understand that additional embodiments ofthe present invention may be practiced without several of the detailsdescribed below.

Many embodiments of the invention described below may take the form ofcomputer-executable instructions, such as routines executed by aprogrammable computer (e.g., a flight guidance computer). Those skilledin the relevant art will appreciate that the invention can be practicedon other computer system configurations as well. The invention can beembodied in a special-purpose computer or data processor that isspecifically programmed, configured or constructed to perform one ormore of the computer-executable instructions described below.Accordingly, the term “computer” as generally used herein refers to anydata processor and can include Internet appliances, hand-held devices(including palmtop computers, wearable computers, cellular or mobilephones, multi-processor systems, processor-based or programmableconsumer electronics, network computers, mini-computers and the like).

The invention can also be practiced in distributed computingenvironments, where tasks or modules perform by remote processingdevices that are linked through a communications network. In adistributed computing environment, program modules or subroutines may belocated in both local and remote memory storage devices. Aspects of theinvention described below may be stored or distributed oncomputer-readable media, including magnetic and optically readable andremovable computer disks, as well as distributed electronically overnetworks. Data structures and transmissions of data particular toaspects of the invention are also encompassed within the scope of theinvention.

FIG. 2A is a schematic illustration of an aircraft 102 having a flightguidance system 100 configured in accordance with an embodiment of theinvention. In one aspect of this embodiment, the flight guidance system100 can include a flight guidance computer 110 linked to one or morecontrol systems 101, shown in FIG. 2A as a lateral motion or rollcontrol system 101 a, a vertical motion or pitch control system 101 b,and an airspeed or engine control system/autothrottle 101 c. The lateralmotion control system 101 a can be coupled to lateral control surfaces104 (e.g., the ailerons and/or rudder of the aircraft 102). The verticalmotion controller 101 b can be coupled to pitch control surfaces 105 ofthe aircraft 102 (e.g., the aircraft elevators). The airspeed controller101 c can be coupled to engines 103 of the aircraft 102.

The flight guidance computer 110 can include a memory and a processor,and can be linked to one or more display devices 111, I/O devices 113and/or other computers of the system 100, as described in greater detailbelow. The I/O devices 113 can be housed in a flight deck 120 of theaircraft 102, and can be used by the pilot or other operator to provideinstructions to the flight guidance system 100. Instructions can also beprovided via telemetry from ground-based stations, or via satellite,data link or gate link. Accordingly, the flight guidance computer 110can include a receiver portion that receives inputs from an operator oranother source, a processor portion that processes signals (e.g., inputsignals) and/or a display portion that displays information (e.g., tothe operator).

FIG. 2B is a forward elevational view of an embodiment of the flightdeck 120 shown in FIG. 2A. In one aspect of this embodiment, the flightdeck 120 includes forward windows 121 providing a forward field of viewout of the aircraft 102 (FIG. 2A) for operators seated in a first seat124 a and/or a second seat 124 b. In other embodiments, the forwardwindows 121 can be replaced by one or more external vision screens thatinclude a visual display of a forward field of view out of the aircraft102. A glare shield 122 can be positioned adjacent to the forwardwindows 121 to reduce glare on one or more flight instruments 127positioned on a control pedestal 126 and a forward instrument panel 123.

The flight instruments 127 can include primary flight displays (PFDs)125 that provide the operators with actual flight parameter information.The flight instruments 127 can further include a mode control panel(MCP) 130 having input devices 132 for receiving inputs from theoperators, and a plurality of displays 131 for providing flight controlinformation to the operators. The inputs received from the operators atthe mode control panel 130 are primarily tactical inputs, e.g., inputsthat are implemented by the control system immediately upon activationby the operators. A flight management computer (FMC) 150 includescontrol display units (CDUs) 155 a, 155 b positioned on the controlpedestal 126. The CDUs 155 a, 155 b include a flight plan list display151 for displaying information corresponding to upcoming segments of theaircraft flight plan. The CDUs 155 a, 155 b also include input devices152 (e.g., alphanumeric keys) that allow the operators to enterinformation corresponding to these segments. The inputs received at theflight management computer 150 are primarily strategic inputs, e.g.,inputs that are implemented at a later time, for example, upon achievinga flight plan target or completing a previous flight plan segment.

FIG. 3 is a block diagram illustrating generally how components of theflight guidance system 100 interact with each other, in accordance withan embodiment of the invention. In one aspect of this embodiment, theflight guidance computer 110 can receive tactical inputs 190 provided bythe operator via the mode control panel 130 or another input device. Theflight guidance computer 110 can also receive strategic inputs 191 fromthe flight management computer 150, which can in turn receive inputsdirectly from the operators or from other sources, (e.g., via telemetry)as described above. The flight guidance computer 110 can present currentand future strategic information on the flight plan list display 151(FIG. 2B), as indicated in block 192. The flight guidance computer 110can also display the current tactical and/or strategic flightinformation, together with strategic flight control information for thenext upcoming segment of the flight (block 193) on the mode controlpanel 130. In one aspect of this embodiment, the manner in which theinformation is displayed on the mode control panel 130 and the flightplan list display 151 can be at least approximately identical, asdescribed in greater detail below with reference to FIGS. 14A-14B.

The flight guidance computer 110 is coupled to the control systems 101a-101 c, each of which can include a corresponding flight controlcomputer 112 (shown as flight control computers 112 a-112 c) coupled toone or more corresponding actuators 107 (shown as actuators 107 a-107c). The actuators 107 a-107 c provide aerodynamic and thrust outputs tocontrol the lateral motion, vertical motion, and airspeed of theaircraft, as shown in blocks 194 a-194 c. Accordingly, the flightguidance computer 110 can (a) receive inputs from a plurality ofsources, (b) display information to the operators, and (c) coordinatethe delivery of the inputs to the appropriate control devices.

FIG. 4 is a block diagram illustrating a process 490 for displayingtactical and strategic flight control information in a similar oridentical manner. The process 490 includes displaying a first indicatorto an operator of an aircraft, with the first indicator corresponding toa first instruction input by the operator for controlling a firstaircraft behavior (process portion 491). For example, the firstindicator can include alphanumeric symbols representing instructions forcontrolling the lateral motion, vertical motion and/or airspeed of theaircraft. The first instruction is implemented upon receiving anactivation instruction from the operator. For example, the firstinstruction can be implemented when the operator pushes a switch on themode control panel 130 (FIG. 3). This type of operation is sometimesreferred to herein as “unlinked” operation because the aircraft isresponding to tactical instructions that are typically not tied directlyto a predetermined flight plan for the aircraft.

In process portion 492, a second indicator is displayed to the operator,with the second indicator corresponding to a second instruction forcontrolling a second aircraft behavior at least approximately the sameas the first. The second instruction is to be implemented at a futuretime. For example, both the first and second behaviors can correspond toan aircraft climb, descend, turn, or other behavior command. The secondinstruction can include a strategic input received from the flightmanagement computer 150 (FIG. 2B). The second instruction can correspondto a segment of the aircraft flight plan that has not yet been executed,but that will be executed automatically when the segment currently beingflown by the aircraft is completed, or upon achieving another target.This type of operation is sometimes referred to herein as “linked”operation because the aircraft is responding to strategic instructionsthat form part of a predetermined flight plan.

As shown in block 492, the first indicator is at least approximately thesame as the second indicator. Accordingly, when the operator views anindication of the manner in which the aircraft is or will be controlled,that indication is consistent whether the indication is for a tacticalinstruction input by the operator for immediate (or nearly immediate)implementation, or a strategic instruction to be implemented by theflight guidance system in accordance with a preset flight plan.

In process portion 493, the first instruction is implemented, and inprocess portion 494, the second instruction is implemented. Theinstructions can be implemented by passing the instructions from theflight guidance computer 110 (FIG. 3) to the flight control computers112 a-112 c (FIG. 3), as described above. In some cases, theinstructions provided to control aircraft motion in any axis areindependent of the instructions provided to control motion in any otheraxis. In other cases, the instructions for motion about different axescan be automatically coupled.

In one aspect of the foregoing embodiments, implementing theinstructions can include automatically carrying out the instructions,for example, if the operator has engaged the autopilot or autoflightcapabilities of the aircraft. In another embodiment, implementing theinstructions can include providing a visual guide (e.g., on the PFDs 125described above with reference of FIG. 2B) that allows the operator tomanually fly the aircraft in accordance with the instructions. Such aguide can include a conventional crosshair target for the lateral andvertical motion of the aircraft, and/or a target thrust indicator foraircraft speed.

The indicators described above with reference to FIG. 4 can include modeand submode indicators (which identify the type of maneuver the aircraftis or will be performing) and a target indicator (which identifies thetarget to which the maneuver is directed). FIG. 5 illustrates a chart590 comparing lateral motion mode and submode indicators 591 (inaccordance with an embodiment of the invention) with existing lateralmode indicators 591 a (generally similar to those described above withreference to FIG. 1A). Modes are indicated by capital letters andsubmodes by lower case letters. Certain modes and/or submodes areavailable only for linked operation or only for unlinked operation (inone embodiment), as indicated by superscripts “1” and “2”, respectively.

One feature of the mode and submode indicators 591 is that they aresignificantly less numerous than the existing mode indicators 591 a.Accordingly, the operator can provide instructions and understandinformation in a simplified manner, reducing the amount of training timerequired to become proficient. Another feature of the mode and submodeindicators 591 is that they are the same (e.g., as displayed to theoperator and as selected by the operator), whether the aircraft isoperating in a linked manner or an unlinked manner. This arrangement canprovide for more consistency between linked and unlinked operations,further reducing the time required for the operator to become proficientin handling automatic aircraft functions.

Another feature of the mode and submode indicators 591 is that they arearranged hierarchically. For example, if the operator wishes to executea left turn (represented by mode “L TURN”) or a right turn (representedby mode “R TURN”), the operator can optionally elect to have the turnconstrained (submode “constr”) if flying in a linked manner. In aconstrained turn, the bank angle is modulated in accordance withstrategic targets to achieve “DME” arcs, curved noise abatementdepartures, complex curved approaches and other pre-selected maneuvers.When the aircraft is operating in an unlinked manner, the operator canoptionally elect to have the turn bank angle limited to a value input bythe operator (submode “ba”). This hierarchical organization allows theoperator to first select the overall type of maneuver or behavior to beexecuted, and then select the details. Such an arrangement can be moreintuitive for the operator than existing modes, and can accordinglyfurther reduce training time.

Still another feature of the mode and submode indicators 591 is thatthey can have simple, specific and mnemonically consistent meanings. Forexample, the “L TURN” and “R TURN” modes describe, simply andmnemonically, left turns and right turns, respectively. The “TRACK” modeincludes straight flight tracks (e.g., great circle lines), includingcapturing and maintaining straight flight tracks. The “HDG” modemaintains a selected heading. Under the “HDG” mode, the path of theaircraft does not account for the effects of wind, while under the“TRACK” mode, wind direction is accounted for.

The “LAND” mode (available only during linked operation, in oneembodiment) automatically controls a de-crab maneuver just prior totouchdown, and controls runway centerline tracking after landing. The“LAND” mode (and other modes included in the flight plan for actionsprior to and subsequent to actual landing) have associated with themsufficient runway information to allow the aircraft to automaticallyland on a selected runway and conduct pre-landing lead-in and/orpost-landing follow-up operations. These modes also have associated withthem instructions for an aircraft go-around in the case of a missedapproach. One feature of this arrangement is that the “LAND” mode andother modes can be a part of the preset flight plan loaded into theflight management computer 150. This is unlike existing auto landfeatures which must be input by the operator at the mode control panel.An advantage of this arrangement is that it can reduce the pilotworkload during flight because it can be established prior to flight aspart of the flight plan. Another advantage is that the go-around featurecan be automatically implemented when the operator activates a go-aroundswitch in the flight deck. If necessary, the flight plan information canbe updated during flight, for example, if the aircraft is redirected toan alternate landing site.

FIG. 6 illustrates a chart 690 comparing vertical motion mode andsubmode indicators 691 with existing mode indicators 691 a generallysimilar to those described above with reference to FIG. 1B. The verticalmotion mode and submode indicators 691 can be (a) fewer in number thanthe existing mode indicators 691 a, (b) nested in a hierarchicalfashion, and (c) consistent for both linked and unlinked operation, in amanner generally similar to that described above with reference to FIG.5. In particular, modes “CLB” and “DES” control climb and descent,respectively, of the aircraft. Without selecting a submode, these modescan be used for takeoff climb, go-around, terrain avoidance, wind shearescape, normal climb, unconstrained cruise descents, and emergencydescents. If the aircraft is flying in a linked manner, the “constr”submode, which can be used for any climb or descent where thrust ismodulated to meet a specific way point target is available via the FMC.Alternatively, the “profile” submode for final approach, tunnel climbsand descents, or drift up (e.g., continuous optimal altitude cruiseclimb) is available. During unlinked operation, the pilot can select the“vs” or “fpa” submodes to climb or descend with a specific verticalspeed or flight path angle, respectively.

The “ALT” mode controls all level flight, including capturing andmaintaining a particular altitude. The “LAND” mode, available only forunlinked operation in one embodiment, includes flare, touchdown andde-rotation after touchdown.

As described above, the modes and submodes can be arrangedhierarchically to provide a simpler, more intuitive manner fordisplaying and receiving flight control information. FIG. 7 is a flowdiagram illustrating a process 790 for presenting to an operatorhierarchically organized options for controlling the flight of anaircraft, in accordance with an embodiment of the invention. Processportion 791 includes presenting a plurality of first level options(e.g., mode indicators) for controlling an aspect of the aircraft'smotion. At least one first level option has associated with it aplurality of second level options (e.g., submodes). The first leveloptions can be displayed in a menu-type format, or by settings on one ormore switches, or by other arrangements.

In any of these arrangements, the operator can select from among thefirst level options. Accordingly, the process 790 further includesreceiving a first input corresponding to a selection of one of the firstlevel options (process portion 792). Once the first input has beenreceived, the process 790 can further include presenting a plurality ofsecond level options (e.g., submode indicators) corresponding to the onefirst level option selected in process portion 792 (process portion793). In one aspect of this embodiment, the second level options foreach first level option can be unique. In other embodiments, at leastsome of the second level options can be shared among first leveloptions. In any of these embodiments, in process portion 794, a secondinput corresponding to a selection of one of the second level options isreceived. The selected first and second level options can then beactivated to control an aspect of the aircraft's motion.

One advantage of the foregoing hierarchical structure is that it can beeasier to understand. Accordingly, it may require less time and expenseto train operators in its use. Another advantage is that such astructure lends itself to future upgrades. For example, if new submodesare developed at a later date, they can be added to the system withrelative ease and without disrupting the organization of the first levelmodes. A further advantage is that the hierarchical structure of themode options can be implemented on a mode control panel 130 withoutrequiring changes to existing PFDs 125 (FIG. 2B) or head up displays.Accordingly, the mode control panel 130 and associated modes andsubmodes can more easily be retrofitted on existing flight decks. A modecontrol panel 130 configured to present the foregoing modes and receivecorresponding inputs is described in greater detail below with referenceto FIG. 8.

FIG. 8 is a partially schematic illustration of a mode control panel 130configured in accordance with an embodiment of the invention. The modecontrol panel 130 can include a lateral motion portion 860, a verticalmotion portion 870, an airspeed portion 880, and a general controlportion 845. The general control portion 845 can include a performanceselector 846 which can be manipulated by the pilot to determine howaggressively the aircraft carries out control inputs. In a particularaspect of this embodiment, each setting of the performance selector 846establishes performance behavior that is the same or approximately thesame for lateral motion, vertical motion and airspeed. An autothrottleswitch 848 is used by the pilot to engage the autothrottles, and anautoflight switch 847 is used by the operator to engage the autopilotand autothrottle capabilities of the system 100.

Each of the remaining portions 860, 870 and 880 can include displays 831(shown as a lateral motion display 831 a, a vertical motion display 831b, and an airspeed display 831 c), and input devices 832 (shown aslateral motion input devices 832 a, vertical motion input devices 832 b,and airspeed input devices 832 c). Each display 831 can include currentcontrol indicators 833 (shown as lateral, vertical and airspeed currentcontrol indicators 833 a, 833 b and 833 c, respectively) and nextcontrol indicators 834 (shown as next lateral, vertical and airspeedcontrol indicators 834 a, 834 b and 834 c, respectively). The currentcontrol indicators 833 pertain to the maneuver currently being executedby the aircraft, and the next control indicators pertain to the nextmaneuver to be executed by the aircraft. In a particular aspect of thisembodiment, the manner in which the next indicators are displayed canindicate which aspect of the upcoming maneuver will be executed first.For example, if the next lateral control indicator 834 a identifies anupcoming change in heading, and the next vertical control indicator 834b identifies an upcoming change in altitude to be implemented after thechange in heading, the next lateral control indicator 834 a can appearin a different font or color to indicate that the change in heading willbe executed before the change in altitude. If these changes will beexecuted at the same time, they can be displayed in the same manner.Further details of the current control indicators 833 and next controlindicators 834 are provided below with reference to FIGS. 9A-11B.

FIG. 9A illustrates the lateral motion portion 860 of the mode controlpanel 130 described above with reference to FIG. 8 as it appears duringlinked operation in accordance with an embodiment of the invention. Thecurrent lateral control indicators 833 a are arranged on one line, andthe next lateral control indicators 834 a are arranged below. Thecurrent lateral control indicators 833 a include a current lateral modeindicator 961 a, a current lateral submode indicator 991 a (shown blankin FIG. 9A), a current lateral link indicator 962 a and a currentlateral target indicator 963 a. The next lateral control indicators 834a include a next lateral mode indicator 961 b, a next lateral submodeindicator 991 b (also blank), a next lateral link indicator 962 b, and anext lateral target indicator 963 b.

The lateral current mode and submode indicators 961 a, 991 a indicatethe lateral mode under which the aircraft is currently operating, andthe current lateral target 963 a indicates the lateral target to whichthe aircraft is being directed. The current lateral link indicator 962 aindicates that lateral control of the aircraft is linked to the flightplan via the flight management computer 150 (FIG. 2B). The next lateralmode indicator 961 b and submode indicator 991 b indicate the lateralmode and submode under which the aircraft will operate upon attainingthe current lateral target 963 a. At that point, the aircraft will becontrolled to the next lateral target 963 b. The next lateral linkindicator 962 b indicates that this operation will also be linked to theflight plan. The operator can link the operation of the aircraft to theflight plan by pressing a link switch 966 a, which, if the aircraft isnot already operating in a linked manner, will cause the aircraft to flyto the next available segment programmed into the flight managementcomputer 150.

During linked operation, the modes, submodes and targets displayed inthe lateral motion display 831 a are obtained directly from the flightmanagement computer 150. During unlinked operation, the modes andsubmodes can be selected by the operator when the operator actuatesswitches at the mode control panel 130. For example, the operator cantoggle between the “HDG” or “TRK” modes by toggling a lateral maintainselector switch 966 b. The selected and available modes appear in anadjacent lateral maintain display 964 with the selected mode highlighted(e.g., by appearing in a larger font) as shown in FIG. 9A. The color ofthe mode (or submode) indicator can identify to the operator (a) whetherthe mode (or submode) is available to be selected, and/or (b) whetheroperation of the mode (or submode) is linked or unlinked. The operatorcan select a bank angle submode using a bank limit selector switch 966c. The selected and available bank limit submodes appear in a bank limitdisplay 965. The operator can actuate a lateral selector 966 f toindicate the direction and target for left and right turns, and canactivate a lateral hold switch 966 e to roll the aircraft out of acurrent turn. If the aircraft is in linked operation, pushing thelateral selector 966 f or lateral hold switch 966 e will automaticallyunlink the lateral motion of the aircraft from the flight managementcomputer 150.

In one aspect of the foregoing arrangement, the current lateral target963 a can be automatically updated when the operator activates thelateral hold switch 966 e. For example, the current lateral target 963 acan be updated immediately (or nearly immediately) after the lateralhold switch 966 e has been activated to provide an estimate of the newlateral target to which the aircraft will be directed upon completion ofthe rollout maneuver. In another aspect of this embodiment, which can beimplemented in addition to or in lieu of the foregoing aspect, thecurrent lateral target 963 a can be updated once the rollout maneuverhas been completed to indicate the actual new target to which theaircraft is being directed.

FIG. 9B illustrates the lateral motion display 831 a during unlinkedoperation, in accordance with an embodiment of the invention. An unlinkindicator 977 highlights to the operator that the current operation isunlinked, and the current lateral control indicators 833 a indicate thecurrent lateral mode 961 a and current lateral target 963 a. A linkprompt 967 a indicates that the pilot can link to the flight plan bypressing the link switch 966 a. In one embodiment, if the distance tothe flight plan route is less than 2.5 nautical miles, the aircraft willfly in mode “L TURN,” “R TURN,” “HDG” or “TRK” to get to the flight planroute. If the distance is greater than 2.5 miles, the flight guidancecomputer 110 (FIG. 3) creates a new leg and intercept way point andautomatically links the leg with the route.

In another embodiment, the lateral motion display 831 a can also includenext lateral control indicators 834 a (shown blank in FIG. 9B)identifying the next available segment in the flight plan. Accordingly,the operator can easily see which instruction will be implemented if heor she chooses to convert from unlinked operation to linked operation bypressing the link switch 966 a.

During unlinked operation, the operator can set up a right or left turnby rotating the lateral selector 966 f to the right or left,respectively. As the operator rotates the lateral selector 966 f, apreview display 969 indicates the sense of the turn (e.g., left orright), the target to which the turn will be directed, and whether uponcompletion of the turn the aircraft will be in “HDC” mode or “TRK” mode.In a particular aspect of this embodiment, the sense of the turn willremain the same as long as the operator keeps rotating the lateralselector 966 f in the same direction, even if the operator rotatesbeyond a value that is 180° from the current target. That is, if theoperator inputs a 270° left turn by rotating the lateral selector 966 fto the left, the aircraft will (upon activation of the instruction) turn270° to the left, not 90° to the right. This arrangement can accordinglybe more intuitive for the operator than some existing systems for whichthe sense of the turn can depend on the extent of the turn. The pilotcan pull the lateral selector 966 f to blank the lateral preview display969, and can push the lateral selector 966 f to (a) unlink the lateralmotion of the aircraft, if it is not already unlinked, (b) activate theinstruction in the lateral preview window 969 (causing this informationto appear at the current control indicator display 833 a), and (c) blankthe lateral preview display 969.

The lateral selector 966 f can be configured to be easily accessible andidentifiable to the operator. For example, the lateral selector 966 fcan include a flange 995 having a compass-like rosette, which signifiesthe lateral aspect of the motion it controls and distinguishes it fromother switches on the mode control panel 130. The flange 995 can projectbelow a lower edge 935 of the mode control panel 130, allowing theoperator to easily rotate the lateral selector 966 f by engaging theflange with a single finger. Alternatively, the operator can rotate thelateral selector 966 f by grasping an outwardly extending knob 996.

FIG. 10A illustrates the vertical motion portion 870 of the mode controlpanel 130 during linked operation in accordance with an embodiment ofthe invention. The overall layout of the vertical motion display 831 band the operation of its input devices are generally similar to thosedescribed above with reference to the lateral motion portion 860.Accordingly, the vertical motion display 831 b can include a currentvertical control indicator 833 b and a next vertical control indicator834 b positioned just below. The current vertical control indicator 833b can include a current vertical mode indicator 1071 a, a currentvertical submode indicator 1091 a, a current vertical link indicator1072 a, and a current vertical target 1073 a. The next vertical controlindicator 834 b can include a next vertical mode indicator 1071 b, anext vertical submode indicator 1091 b (blank in FIG. 10A), a nextvertical link indicator 1072 b, and a next vertical target 1073 b.

If the vertical motion of the aircraft is not already linked to theflight management computer, the operator can create the link by pressingthe link switch 1076 a. The operator can also rotate the link switch1076 a to select a new target altitude, which appears in a limitaltitude display 1075. The limit altitude is inserted into the flightplan. Pulling the link switch 1076 a blanks the limit altitude display1075. Further details of this feature are described below with referenceto FIGS. 14A-14B.

FIG. 10B illustrates the vertical motion portion 870 of the mode controlpanel 130 during unlinked operation. During unlinked operation, anunlink indicator 1077 appears below the current vertical controlindicator 833 b, and a link prompt 1067 a appears adjacent to the linkswitch 1076 a. The operator can select modes and submodes using theswitches at the vertical motion portion 870 of the mode panel 130, in amanner generally similar to that described above with reference to thelateral motion portion 860. For example, the operator can toggle betweencontrolling the aircraft's vertical motion by vertical speed or flightpath angle by toggling a vertical maintain selector switch 1076 b andchanging a corresponding display in a vertical maintain display 1074.The operator can set the value of the vertical speed or flight pathangle by rotating a rotary switch 1076 c. The operator can engage the“vs” or “fpa” submodes by pressing an engage switch 1076 d.

The operator can control the altitude target to which the aircraft willbe directed with a vertical selector 1076 e. The operator can rotate analtitude selector 1076 f and can adjust an increment selector 1076 g tocontrol whether the value generated by the altitude selector 1076 f isin thousands of feet or hundreds of feet. As the operator adjusts thevertical selector 1076 e, the mode and target are updated in a verticalpreview display 1079. When the operator pushes the vertical selector1076 e, the vertical motion axis of the aircraft is unlinked (if it isnot already unlinked), the information in the vertical preview display1079 is presented in the current vertical indicator 833 b, and thevertical preview display 879 is blanked. Pressing a vertical hold switch1076 h will cause the aircraft to level out and maintain the resultingaltitude. The current vertical target 1073 a can be updated to providean estimated and/or actual level out altitude, in a manner generallysimilar to that described above with reference to the current lateraltarget 963 a shown in FIGS. 9A-9B. If the operator presses a drift downswitch 1076 i, the aircraft will fly as gradual a descent as possible,for example, during engine-out operation. In a particular aspect of thisembodiment, the gradual descent can be automatically implemented basedsolely upon the input received when the operator presses the drift downswitch 1076 i. This is unlike some existing systems which require theoperator to change the corresponding cruise altitude and activate anengine-out mode of the flight management computer 150 (FIG. 3) beforeactually implementing the drift down procedure. Accordingly, theforegoing, simplified arrangement can reduce pilot workload, errorsand/or training time and can allow the drift down feature to be morequickly activated.

FIG. 11A illustrates the airspeed portion 880 of the mode control panel130, displaying flight control information during linked operation, inaccordance with an embodiment of the invention. Several aspects of theairspeed portion 880 are generally similar to the lateral motion portion860 and the vertical motion portion 870 described above. For example,the airspeed display 831 b can include a current airspeed indicator 833c and a next airspeed indicator 834 c positioned below. The operator canpush an airspeed link switch 1186 a to link the commanded airspeedtarget (e.g., via the aircraft engines and/or elevators) to the flightplan, as reflected by the current link indicator 1182 a and next linkindicator 1182 b.

In a particular aspect of this embodiment, the automatic control of theaircraft's airspeed is not characterized by modes, but rather by targetsalong with information indicating the basis for the targets. Forexample, the current airspeed control indicator 833 c can include acurrent target 1183 a and the next airspeed indicator 834 c can includea next target 1183 b. Each of the targets 1183 a, 1183 b can include anumerical value of the airspeed to which the aircraft is beingcontrolled and a textual indicator of the basis for the airspeed. Forexample, “Restr” can indicate a flight plan speed restriction, “Econ”can indicate an economy airspeed setting, “Flap Lim” can indicate alimit speed corresponding to a currently extended flap position, and“Flap Ref” can indicate a maneuvering speed corresponding to a currentlyextended flap position.

The airspeed display 831 c can also include an energy management display1184, which indicates the manner in which the longitudinal motion andvertical motion of the aircraft are controlled, which in turn dependsupon the mode selected for the vertical motion of the aircraft. In oneaspect of this embodiment, the energy management display 1184 caninclude a first indicator 1184 a for a first aircraft control force in afirst direction (e.g., “Pitch”) and a second indicator 1184 b for asecond aircraft control force in a second direction (e.g., “Thrust” or“Drag”). The energy management display 1184 also includes a longitudinaltarget 1184 c (e.g., “Spd” for speed) and a vertical target 1184 d(e.g., “Clb” for climb, “Des” for descent, or “Alt” for fixed altitude).A first (pitch) control link 1184 f (e.g., a line with an arrowhead)indicates whether the pitch attitude of the aircraft is being used tocontrol to a longitudinal target or a vertical target. A second(thrust/drag) control link 1184 e indicates whether the thrust devices(e.g., engines) or drag devices (e.g., speedbrakes) are being used tocontrol the aircraft to a longitudinal target or a vertical target. Forexample, when the aircraft is climbing, the first (pitch) control link1184 f indicates that the pitch of the aircraft is being adjusted tomaintain a target airspeed. The second (thrust/drag) control link 1184 eindicates that the thrust of the aircraft is being controlled tomaintain a target climb rate. The positions of the control links 1184 fand 1184 e can be changed depending upon the manner in which theseparameters are controlled, as described below with reference to FIG.11B.

FIG. 11B illustrates the airspeed control portion 880 during unlinkedoperation in accordance with an embodiment of the invention. In oneaspect of this embodiment, an unlink indicator 1177 highlights the factthat the aircraft is operating in an unlinked manner. During unlinkedoperation, the operator can select a target airspeed by adjusting anairspeed knob 1186 d, and can determine whether the airspeed isidentified by Mach number or indicated airspeed (IAS) by manipulating atoggle switch 1186 b. The operator can also select among a variety ofairspeeds (with associated text modifiers) by pressing an airspeedoptions key 1186 c. By repeatedly pressing the airspeed options key 1186c, the operator can scroll through a list of airspeed options, each ofwhich corresponds automatically to a particular airspeed. These optionscan include “E/O” (engine out), “LRC” (long range cruise), “Co” (companyspecified speed), “Vx” (best flight path angle), “Vy” (best rate ofclimb), “Trb” (turbulent air penetration), and “Gld” (best glide speed).The value selected by manipulating the airspeed options key 1186 c orthe airspeed selector 1186 d can appear in an airspeed preview display1189. Pushing the airspeed selector 1186 d activates the instruction inthe airspeed preview display 1189 and updates the current airspeedcontrol indicator 833 c accordingly.

In one aspect of the foregoing embodiments, some or all of theindicators can be textual indicators, graphical indicators or acombination of textual and graphical indicators. The links 1184 e, 1184f can change color or another characteristic when it is possible for theoperator to change which target 1184 c, 1184 d is coupled to the firstand second indicators 1184 a, 1184 b. In other embodiments, otherindicators can also be displayed in different manners depending onwhether or not the corresponding control option is available to theoperator. For example, in one further embodiment, modes and/or submodescan be displayed in one manner if they are consistent with the selectedtarget, and in another manner if they are inconsistent with the selectedtarget. In a further aspect of this embodiment, the modes and/orsubmodes that are inconsistent with the selected target may beunavailable for selection by the operator. For example, if the operatorchooses a target located above the aircraft's current altitude, the“DES” mode will appear differently to the operator and/or will beunavailable for selection by the operator.

One feature of an embodiment of the mode control panel 130 describedabove with reference to FIGS. 8-11B is that the arrangement andoperation of many of the controls and displays are consistent across atleast two of the motion axes. For example, if the operator wishes tolink operation of any of the motion axes (which can be doneindependently of linking the remaining axes), the operator presses aswitch located toward the top of the mode control panel 130. If theoperator wishes to unlink operation of any of the axes (which can bedone independently of unlinking the remaining axes), the operatorpresses a switch located toward the bottom of the mode control panel130. The target to which the aircraft is currently being directed isconsistently positioned above the target to which the aircraft willsubsequently be directed. For motion axes having modes and submodes, themodes are consistently positioned to the left of the target and to theleft of the link indicator. Each axis can include a preview displayindicating the parameters to which the aircraft will be controlledduring unlinked operation, before the pilot actually initiates suchunlinked operations. An advantage of the foregoing arrangement is thatthe controls for all three axes can be more intuitive and canaccordingly reduce the time required by the pilot to become proficientin the use of the controls.

Another feature of an embodiment of the mode control panel 130 describedabove is that the current targets to which the aircraft is flying can bedisplayed in a continuous manner, simultaneously with displaying currentmode information. An advantage of this feature is that the operator canconsistently locate current target information at the same locationwithin the flight deck. Accordingly, the operator's workload can bereduced.

Still another feature of an embodiment of the mode control panel 130described above is that the lateral motion, vertical motion, andairspeed of the aircraft are displayed sequentially (e.g., from left toright). An advantage of this arrangement is that this ordering isconsistent with the order in which instructions are conventionallyrelayed to the operator by air traffic control (ATC). Accordingly, theoperator can easily view and/or modify the control information whilereceiving instructions from air traffic control, without having tovisually skip over various portions of the mode control panel 130.Instead, the operator can move his or her eyes and/or hand in a serialfashion from one display portion to the next as the instructions arereceived.

FIG. 12 illustrates a process corresponding to the manner of operationdescribed just above. The process 1290 can include displaying at a firstdisplay location first information corresponding to a characteristic ofa lateral motion of the aircraft (process portion 1291), displaying at asecond display location second information corresponding to acharacteristic of a vertical motion of the aircraft (process portion1292), and displaying at a third display location third informationcorresponding to a characteristic of a speed of the aircraft (processportion 1293). The second information can be displayed between thedisplays of the first information and the third information (processportion 1294). In a particular aspect of this embodiment, displaying thefirst information (process portion 1291) can include displaying alateral mode under which the aircraft is currently operating, displayinga lateral target corresponding to the lateral location to which theaircraft is automatically being directed, displaying a subsequentlateral target to which the aircraft will be automatically directedafter attaining the current lateral target, and (in a particularembodiment) displaying a subsequent lateral mode. In a generally similarmanner, displaying the second information can include displaying currentvertical mode information, current vertical target information, andsubsequent vertical target information (and/or mode), and displaying thethird information can include displaying the current airspeed target andsubsequent airspeed target.

As described above, another feature of the system 100 is that it canallow the operator to preview instructions when controlling the aircraftin an unlinked manner, before committing to having the instructionsimplemented. FIG. 13 is a flow diagram illustrating a process 1390corresponding to this arrangement. The process 1390 can includedisplaying a current target to which the aircraft is currently beingdirected at a first display location (process portion 1391) andreceiving an input for a proposed subsequent target (process portion1392). The input for the proposed subsequent target can be provided bythe operator (e.g., at the mode control panel 130 or the flightmanagement computer 150), or by other sources (e.g., via a datalink).The proposed subsequent target and, optionally the sense of the targetcan be displayed at a second display location (e.g., at a previewdisplay window) simultaneously with displaying the current target(process portion 1393). In one aspect of this embodiment, the previewdisplay window initially displays the current target, and then updatesthe value shown as the input is received. In process portion 1394, theprocess 1390 includes receiving an input authorizing implementation ofthe subsequent target (e.g., when the pilot presses a button on the modecontrol panel 130). The display of the current target at the firstdisplay location is then replaced with a display of the subsequenttarget at the first display location (process portion 1395).

An advantage of the arrangement described above with reference to FIG.13 is that, when the aircraft is operating in an unlinked mode, thepilot can preview the target to which he will subsequently direct theaircraft, while viewing the target to which the aircraft is currentlybeing directed and before committing to the new target. This arrangementcan reduce pilot confusion by clearly delineating between a target towhich the aircraft is currently being directed and a proposed new targetto which the aircraft may or may not subsequently be directed, dependingon whether the operator authorizes implementing the new target.

FIG. 14A is a simplified, partially schematic illustration of portionsof the mode control panel 130 and the flight plan list display 151,configured to display information during unlinked operation inaccordance with an embodiment of the invention. In one aspect of thisembodiment, both the mode control panel 130 and the flight plan listdisplay 151 include displays of flight control information arranged inthree columns: a first column corresponding to lateral motion, a secondcolumn corresponding to vertical motion, and a third columncorresponding to the airspeed of the aircraft. The mode control panel130 displays the current control indicators 833 (shown as currentlateral control indicators 833 a, current vertical control indicators833 b, and current airspeed control indicators 833 c), each of whichincludes a corresponding current target indicators 963 a, 1073 a, 1183a, respectively. The mode control panel 130 also displays the nextcontrol indicators 834 (shown as next lateral control indicators 834 a,next vertical control indicators 834 b, and next airspeed controlindicators 834 c), with no next targets shown because the operation isunlinked. Unlink indicators 977, 1077 a and 1177 also highlight theunlinked aspect of the operation.

At least some of the same information (e.g., the targets) displayed onthe mode control panel 130 can be presented on the flight plan listdisplay 151. In a particular aspect of this embodiment, the flight planlist display 151 can include the current control indicators 833 a, 833b, 833 c even if these indicators correspond to instructions input atthe mode control panel 130 for unlinked operation. In a particularaspect of this embodiment, information corresponding to linked operationcan be visually separated from information corresponding to unlinkedoperation, e.g., by a marker 1455 or by use of different colors orfonts. The flight plan list display 151 also includes subsequent controlindicators 1453 for flight plan legs to be executed subsequently to thecurrent flight plan leg.

FIG. 14B illustrates the mode control panel 130 and the flight plan listdisplay 151 during linked operation. The unlink indicators 977, 1077,and 1177 (FIG. 14A) are not displayed on the mode control panel 130while the next targets 963 b, 1073 b and 1183 b are displayed, all ofwhich signifies linked operation. The flight plan list display 151 doesnot display the marker 1455 (FIG. 14A), which further signifies linkedoperation.

One feature of an embodiment of the arrangement described above withreference to FIGS. 14A-14B is that the information shown on the modecontrol panel 130 matches, or at least approximately matches, theinformation shown on the flight plan list display 151, in organization,content or both. Accordingly, operators need not learn to recognizedifferent indicators (or different ordering of indicators) that maycorrespond to similar or identical flight control instructions. Anotherfeature of this embodiment is that the operator can see both tactical(unlinked) and strategic (linked) information at the same display.

In yet another embodiment, the aircraft can include an altitude alertingsystem that is directly coupled to the flight guidance computer 110(FIG. 2A). Accordingly, the altitude alerting system can be coupled toinputs received by and/or displayed at the mode control panel 130,and/or displayed at the flight plan list display 151. In a particularembodiment, the altitude alerting system can be triggered by deviationsfrom the target altitude (e.g., the current target altitude for a levelflight maneuver during climb, descent or cruise), automaticallydisplayed at the flight plan list display 151 and pre-programmed intothe flight guidance computer 110. If the current altitude of theaircraft differs from the target altitude by more than predeterminedamount, the system can alert the operator, e.g., via a visual and/oraural notification. This is unlike some existing systems where thealtitude alerting system is triggered by deviation from an altitudevalue that is manually input by the operator and displayed at a separatealtitude window.

As described above with reference to FIG. 10A, the mode control panel130 can include a limit altitude display 1075 at which the operator candisplay clearance limit altitudes (e.g., as imposed by air trafficcontrol) during flight, by rotating the link switch 1076 a. Accordingly,the clearance altitude limit can represent an altitude at which theaircraft will level off, e.g., through operation of the flightmanagement computer 150 or the autopilot. The operator can alsodeactivate the clearance limit by blanking the limit altitude display1075, which is unlike existing systems, and which allows the operatoradditional flexibility. In particular, the operator can activate theclearance limit altitude, set the desired value, and deactivate thevalue when it is no longer used. In one aspect of this embodiment, theaircraft altitude is then controlled by the flight segmentspre-programmed into the flight management computer 150. A visualindicator (e.g., the color of the display 1035) can indicate to theoperator whether or not the clearance limit is available or active orinactive. In one aspect of this embodiment, this feature is availableonly during linked operation.

If the clearance limit value represents the next level-off altitude inthe flight plan (during climb or descent), it becomes the currentvertical target. Accordingly, it is displayed at the current targetindicator 1073 a on the mode control panel 130 and is also shown at theappropriate line of the flight plan list at the flight plan list display151. In a particular aspect of this embodiment, the flight segments orlegs subsequent to the clearance limit are highlighted to indicate thatthey are not yet cleared (e.g., by providing a visual separator betweencleared and uncleared segments, and/or by providing cleared segments ina different color than uncleared segments).

If the clearance limit value represents a level-off that occurs afterthe next level-off in the flight plan (during climb or descent), it isshown in the appropriate line of the flight plan list on the flight planlist display 151, and the remaining legs of the flight plan areindicated to be uncleared. As the operator then changes the clearancelimit value at the limit altitude display 1075, the flight plan listdisplay 151 is automatically updated to indicate new cleared legs (asappropriate) and the clearance value is inserted into the flight planlist display 151. If the aircraft operation is subsequently unlinked,the clearance limit is deleted and, in one embodiment, is notautomatically reinstated if linked operation subsequently isreactivated. An advantage of the foregoing arrangement is that theoperator can clearly see by reference to the flight plan list display151 which legs are cleared and which are not. This arrangement can beparticularly useful when a clearance limit results in multiple flightlegs being cleared.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the invention. Additional related embodiments aredisclosed in co-pending U.S. application Ser. No. 10/746,912, entitled“Apparatuses and Methods for Displaying and Receiving Tactical andStrategic Flight Guidance Information,” filed concurrently herewith andincorporated herein in its entirety by reference. Accordingly, theinvention is not limited except as by the appended claims.

We claim:
 1. A computer-readable storage medium containing instructionsexecutable by a processor for controlling an aircraft system by a methodcomprising: receiving an indication of an altitude clearance limit foran aircraft; displaying the indication of the altitude clearance limitat a display portion of the aircraft; receiving an instruction from anoperator to cease displaying the indication of the altitude clearancelimit for the aircraft; ceasing to display the clearance limit; andcontrolling the aircraft to a pre-programmed altitude.
 2. Thecomputer-readable storage medium of claim 1 wherein the method furthercomprises receiving the indication of a clearance limit directly fromair traffic control.
 3. The computer-readable storage medium of claim 1wherein the method further comprises receiving the indication of aclearance limit from an operator in communication with air trafficcontrol.
 4. The computer-readable storage medium of claim 1, wherein thealtitude clearance limit is displayed during linked operation, andwherein during linked operation, the altitude clearance limit isincorporated into a flight plan of the aircraft for automatic executionat a future time.
 5. The computer-readable storage medium of claim 4,the method further comprising deleting the altitude clearance limit inresponse to the aircraft changing to unlinked operation, and whereinduring unlinked operation instructions controlling the aircraft aredirectly implemented in response to an operator request.
 6. Thecomputer-readable storage medium of claim 1, wherein the method furthercomprises automatically leveling the aircraft at the altitude clearancelimit.
 7. The computer-readable storage medium of claim 1, wherein themethod further comprises providing a visual indicator to indicate to anoperator whether the altitude clearance limit is active or inactive. 8.The computer-readable storage medium of claim 1, wherein the altitudeclearance limit is incorporated into a leg of a flight plan of theaircraft and wherein the method further comprises displaying a visualindication that one or more other legs of the flight plan are notcleared.
 9. A method for controlling an aircraft system, comprising:receiving an indication of an altitude clearance limit for an aircraft;displaying the indication of the altitude clearance limit at a displayportion of the aircraft; automatically controlling the aircraft to leveloff at the altitude clearance limit; receiving an instruction from anoperator to cease displaying the indication of the altitude clearancelimit for the aircraft; ceasing to display the clearance limit; andcontrolling the aircraft to a pre-programmed altitude, wherein thepre-programmed altitude is provided during linked operation by apredetermined flight plan containing one or more strategic instructionsfor automatically controlling the aircraft.
 10. The method of claim 9,wherein the aircraft includes a computer having an least one inputdevice to receive the instruction.
 11. The method of claim 9, furthercomprising providing a visual indicator to indicate to an operatorwhether the altitude clearance limit is active or inactive.
 12. Themethod of claim 9, wherein the altitude clearance limit is incorporatedinto a leg of a flight plan of the aircraft and wherein the methodfurther comprises displaying a visual indication that one or more otherlegs of the flight plan are not cleared.
 13. The method of claim 9,wherein the altitude clearance limit is incorporated into a leg of aflight plan of the aircraft and wherein the method further comprisesdisplaying an indication of the altitude clearance limit on a display inassociation with the leg of the flight plan.
 14. A system forcontrolling an aircraft, comprising: an input device configured toreceive instructions from an operator of the aircraft; a display device;a memory; and a processor coupled among the input device, the displaydevice, the memory, wherein the processor is configured to: receive anindication of an altitude clearance limit from the input device; directthe display device to display the indication of the altitude clearancelimit; receive an instruction from the operator through the input deviceto cease displaying the indication of the altitude clearance limit forthe aircraft; direct the display device to cease display of theclearance limit; and control the aircraft to a pre-programmed altitude.15. The system of claim 14, wherein the altitude clearance limit isdisplayed during linked operation, and wherein during linked operation,the altitude clearance limit is incorporated into a flight plan of theaircraft for automatic execution at a future time.
 16. The system ofclaim 15, wherein the processor is further configured to delete thealtitude clearance limit in response to the aircraft changing tounlinked operation, and wherein during unlinked operation instructionscontrolling the aircraft are directly implemented in response to anoperator request.
 17. The system of claim 14, wherein the altitudeclearance limit is incorporated into a leg of a flight plan of theaircraft and wherein the processor is further configured to direct thedisplay device to display a visual indication that one or more otherlegs of the flight plan are not cleared.
 18. The system of claim 14,wherein the altitude clearance limit is incorporated into a leg of aflight plan of the aircraft and wherein the processor is furtherconfigured to cause the display device to display an indication of thealtitude clearance limit in association with the leg of the flight plan.